Stabilized motor fuel



STAB MOTOR FUEL Theodore B. Tom, Hammond, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application March 26, 1947, Serial No. 737,432

, 8 Claims.

The present invention relates to new and useful compositions of matter, and particularly to stabilized organic substances and to the method of stabilizing organic substances against oxidatlve deterioration in the presence of metals or metal compounds which catalyze such oxidation, for example copper, vanadium, manganese, cobalt, chromium and the like and compounds thereof. More particularly, the invention is directed to stabilized petroleum products and to the method of stabilizing petroleum products.

Organic materials such as petroleum products, for example motor fuels, naphthas, Diesel fuels, fuel oils, electrical insulating oils, turbine oils, lubricating oils, greases, waxes, asphalts, and compounded lubricants, synthetic hydrocarbon oils, vegetable oils, animal oils, marine oils, vegetable and fruit juices, textile fibers, anti-oxidants, rubber and rubber products, soaps, etc. are susceptible to oxidative deterioration, particularly in the presence of metals which are oxidation catalysts, for example copper, vanadium, cobalt, chromium, etc. and compounds thereof. An example of such oxldative deterioration is the formation of gum and/or color in storage or in use of certain types of motor fuels, particularly those obtained from cracking processes. In order to inhibit such gum/or color formation, it has been common practice to add to such juels various types of anti-oxidants such as for example aminophenols, substituted aminophenols, naphthols, aromatic hydroxy compounds, hard wood tar distillates and other known antioxidants. It has been observed that when motor fuels containing anti-oxidants are stored in metal containers or come in contact with metal surfaces containing copper or copper alloys, the inhibiting effect of the anti-oxidant is decreased to the point where gum forms in such fuels in spite of any anti-oxidant they may contain.

This deterioration of anti-oxidants is also encountered in fuels which have been subjected to the copper chloride sweetening process. Such oxidative catalyzing effect is also encountered in viscous hydrocarbon oils even though they may contain anti-oxidants, such as for example phenyl alpha naphthylamine, cyclo hexylamine, alkyl amines, etc. When oils, for example refrigerator oils, turbine oils, electrical insulating oils, internal combustion engine lubricants, etc. are brought in contact with metals such as for example copper, chromium, vanadium, or. compounds thereof, they oxidize with the formation of sludge and/or color.

It is an object of the present invention to provide organic substances resistant to oxidative deo compositions. Still another object of the invention is to provide petroleum products which are resistant to oxidative deterioratiom- A further object of the invention is to provide a method of inhibiting the oxidative deterioration of pctroleum products containing or coming in contact with metals or metal compounds which catalyze such oxldative deterioration, Other objects and advantages of the invention will become apparent from the following description thereof.

I have discovered that the oxidative deterioration of organic substances can be effectively inhibited by adding to such organic substances, for example petroleum products, a small but suincient inhibiting amount, for example from about 0.0001% to about 5% and preferably from about 0.005% to about .5% of an organo-arsenic compound having the following formula:

in which R1 is an organic radical of the group consisting of aliphatic, cyclo-aliphatic, aromatic and heterocyclic radicals and mixtures thereof,

R3 and R4 are hydrogen, and X is at least one element of the group consisting of oxygen and sulfur. It is to be understood that the term organic radicals" used herein includes organic radicals containing substituent groups such as for example oxy, hydroxyl, thio, amino, halogen or other groups.

Specific examples of compounds falling within the above named arsenic compounds are the following:

Organo arsonic acids e. g.:

benzylarsonic acid tolylarsonic acid butylarsonic acid hydroxyphenylarsonic 5 phenylarsonic acid acid allylarsonic acid terpenylarsonic acid octylarsonic acid ethoxyphenylarsonic phenylthioarsonic acid acid allylthioarsonic acid 3-amyl-A-hydroxybutylthioarsonic acid phenylarsonic acid,

cetylarsonic acid etc.

Another object of the in- Organo thion-arsonic acid e. 3.:

hexyl thion-arsonic acid phenyl thion-arsonic acid, etc.

Organo thion-thiol-arsonic acid e. 3.:

lauryl thion-thiol-arsonic acid xylyl thion-thiol-arsonic acid, etc.

Organo-trithio-arsonic acid, e. g.:

butyl-trithio-arsonic acid phenyl trithio-arsonic acid,. etc.

Organo monothiol-arsonic acid e. 3.:

phenyl monothiol-arsonic acid decyl monothiol-arsonic acid xylyl monothiol-arsonic acid, etc.

organo dithiol-arsonic acid e. g.:

lauryl dithiol-arsonic acid isoamyl dithiol-arsonic acid While all of the organo arsonic compounds of the above type are effective inhibitors, it is not to be implied that all are equivalents since the specific activity of the various compounds varies to some extent.

Although the present invention finds application in compositions wherein the organic substance, for example petroleum fractions, constitute a major proportion, that is, more than 50% of the composition, it can also be suitably employed for the stabilization of compositions in which the organic substance susceptible to oxidation constitutes a minor pro ortion.

The effectiveness of the herein described compounds as inhibitors against oxidative deterioration, particularly in the presence of metal catalysts, is illustrated by the data in Table I. These data were obtained by subjecting a motor fuel containing an anti-oxidant in the presence of a metal or metal compound to the A. S. T. M. test for determining the stability of motor fuels by accelerated oxidation. This test has A. S. T. M. designation D525-42T and is fully described on page 965 of the A. S. T. M. Standards 1942- Part III. In obtaining the data of Table I the control was a motor fuel containing 0.01% butyl aminophenol as the anti-oxidant.

Table I A. S. T. M. Induction Period, Minutes Sample 1. 0.

No Soluble Metallic Copper Copper 1 Copper 1 l Control 635-680 85-100 155 2 Control+0.005% Benzylarsonic acid 465 3 Control+0.005% Butylarsonic acid 570 4 C0ntrol+0.0025% Phenylarsonic i 670 5 Contrc1+0.005% Phenylarsonie acid 845 895 6 Control-l-l).005% All arsonic acid......... S 7 Control+0.005% p-liydroxyphenyl-arsonic acid 880 8 Control+0.005% p-ethox yphenylarsonlc acid- 790 9 Control-i-0.005% 3-amyl- 4 -hydroxy -phenylarsonic acid. 830 l0 Cr)ntrol+0.005% Commercial Deactivator- 790 265 Soluble copper-copper oleate (4 mgs. Cu. per liter fuel). 2 Metallic copper-l8 inches No. 18 copper wire.

The above data demonstrate the metal deactivating affect .of some of the arsonic compounds of the present invention. It will be noted Table II A. S. '1. M. Induction Period-Minutes Sample N 0 Copper $235:

1 ontrol 200 80 2 Control+0.005% Phenyla son- The organo arsonic compounds of the type herein described are also effective in certain types of naphtha and hydrocarbon solvents which are required to pass vigorous copper strip tests such as the A. S.. T. M. D-235 test described in the A. S. T. M. Standards 1942, Part III, page 85 under (Method c) or the A. S. T. M. Method D-484 described on page 82 (Method 1)) of the same A. S. T. M. Standards for 1942. Despite careful treating operations, frequently so-called finished naphthas contain suflicient amounts of sulfur and/or polysulfides to give bad copper strip test results. By adding a small amount of the herein described additive, naphthas which contain suilicient sulfur or polysulfides to prevent them from passing copper strip tests readily passed the test. The effectiveness of these organo arsonic compounds in permitting finished naphthas to pass these copper strip tests under conditions in which they would fail to pass the test without the parentheses in Table III are based on the following ratings: copper strips were rated according to an arbitrary scale in which 0 represents a perfect strip and 12 a black, highly corroded one with variations in between, the intermediate strips varying from slightly discolored to highly discolored. Table III N 0. pp rip Rating Control Transparent Black (Stage 9). Control+Commercial Additive. Silver (Stage 6). Control+0.005% p-hydroxy- Claret Red (Stage 3).

phenylarsonic acid. Control+0.025% p-hyd roxy- Perfect (Stage 0). phenylarsonic acid.

The above data clearly demonstrate the ability of organo arsonic compound-naphtha compositions to pass stringent copper strip tests. For this purpose about 0.001% to about 0.5% by weight, preferably from about 0.005% to about 0.1% by weight of the organo arsonic compound can be employed for improving the response oi naphthas to copper strip corrosion tests.

While I have described my invention in connection with the stabilization of motor fuels and naphthas, it is not limited thereto but is applicable to the stabilization of organic substances such as those hereinbefore mentioned against oxidative deterioration whether or not such oxidation is accelerated by a metal or a metal compound catalyst. When employed in lubricants such as lubricating oils and greases, turbine oils, electrical insulating oils and the like, the herein described compounds can be used in conjunction with anti-oxidants, anti-rust compounds, pour point depressants, detergents, anti-wear agents, anti-foam agents, extreme pressure additives, bearing corrosion inhibitors, etc.

While I have described the preferred embodiabout 0.005% to about 0.5% of an organo arsonic acid having the general formula Rla=' in in which R. is an organic radical of the group consisting of an aliphatic radical and an aromatic radical.

2. A motor fuel as described in claim 1 in which the arsonic acid is an aliphatic arsonic acid.

3. A motor fuel as described in claim 2 in which the arsonic acid is allylarsonic acid.

- ments of my invention and the preferred mode of anodes-r 4. A motor fuel as described in claim 1 in which the arsonic acid is an aromatic arsonic acid.

5. A motor fuel as described in claim 4 in which the arsonic acid is phenylarsonic acid.

6. A motor fuel as described in claim 4 in which the arsonic acid is p-ethoxyphenylarsonic acid. 7. A motor fuel composition comprising a major proportion of a hydrocarbon motor fuel normally susceptible to oxidative deterioration in the presence of an oxidation catalyst, and from about 0.005% to about 0.5% of an organo arsonic acid having the general formula on R-As=0 lll in which R. is an organic radical selected from the group consisting of an aliphatic radical and an aromatic radical.

8. A motor fuel composition as described in claim 5 in which the oxidation catalyst is of the groupeconsisting of copper and a, copper com- The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,988,176 Merrill Jan. 15, 1935 2,312,207 Clayton Feb. 23, 1943 2,346,156 Farrington Apr. 11, 1944 2,396,258 Friedheim Mar. 12, 1946 

1. A HYDROCARBON MOTOR FUEL CONTAINING FROM ABOUT 0.005% TO ABOUT 0.5% OF AN ORGANO ARSONIC ACID HAVING THE GENERAL FORMULA 